A pigment, which is used in a paint, an ink jet ink, a color filter, and so forth, is a color material having better durability than a dye in light resistance, weather resistance, heat resistance, water resistance, and so on. However, especially with regard to heat resistance, for example, a pigment used in a color filter becomes coarse or aggregates in a certain instance during the time of heat treatment at high temperature of 200° C. or higher; and thus, existing pigments have not yet fulfilled the requirements from industries.
Accordingly, proposals have been made with regard to a method such as a method in which pigment's heat resistance is improved by coating around the said pigment particles with a metal compound in a gel form as shown in Patent Document 1 and a method in which a pigment is used as a mixture with a chloride compound as shown in Patent Document 2; however, a pigment having its heat resistance improved without containing a compound other than the said pigment is wanted.
A phthalocyanine pigment widely used in industries has the same problems as mentioned above. Moreover, a phthalocyanine is a material used not only as a color material such as a pigment but also as a charge generating material like an organic photoconductor (OPC), a semiconductor, a catalyst, a solar cell, and so forth; and thus, a phthalocyanine having its heat resistance improved are eagerly wanted.